Process for treating cellulose containing fabrics, threads, and the like, and product therefrom



Patented Dec. 18, 1934 UNITED STATES 1,985,124 PROCESS. FOR TREATING CELLULOSE CON-' TAININ S G FABRICS, THREAD LIKE, AND PRODUCT THEREFROM Switzerland, asaignor to Ernst Weiss, Wattwil,

AND 'rnr:

Heberlein Patent Corporation, New York, N. Y., a corporation of New York -No Drawing.

Application May 13, 1932, Serial No. 611,245.- In Germany November 23, 1931 8 Claims. (Cl. a-zo) This invention-relates to the production of transparent cotton or cellulose-containing goods. Such goods have heretofore appeared on the market and while they have possessed a desirable degree of transparency, they have always possessed a stiff characteristic, which although not undesirable for certain purposes rendered such fabrics diflicult to handle and otherwise somewhat undesirable. For example, where it has been desired to process these old transparent fabrics by passing them through rollers as by printing in roller type printing machines, this has been accomplished with such fabric only with great difllculty.

The principal object of the present invention accordingly is to provide a simple and efficient process for the production of transparent cotton and cellulose-containing material which,

. while possessing the desired transparency, shall nevertheless retain a softness and suppleness near to the original untreated material.

The invention accordingly consists in the novel process or processes hereinafter described by way of example in accordance with certain ways of carryingout the same and also in the resulting products, and will be more particularly pointed out in the appended claims. In order that the scope of the use and application of the invention to goods for the produc- 5 tion of soft transparent effects may be more readily underestood, 1 will first refer to some of the prior processes for producing permanent finishes and upon which this invention constitutes an improvement. It has been pointed out in United States Patent 1,144,655 granted to Georges Heberlein that when-cotton is treated with sulfuric acid above 50.5 B. and preferably at about 54 B. that a transparentjpermanent effect or permanent organdy would result.

0 This material, however, while transparent nevertheless had the stiffness which it is desired to avoid by the present invention.

It was further pointed out in the United States patent to Eduard Heberlein, #1,265,082, that a 45 permanent transparent effect could be obtained if the cotton fabric was treatedfor a suflicient period with caustic alkali cooled below 0 C.

and with such concentration as would mercerize the cottonat the ordinary temperature. It

. 50 was also mentioned that if in conjunction with the treatment by such cold caustic alkali; the fabric was also treated with sulfuric acid of above 50.5 B. at a low temperature, an en- 'hanced transparency would result. The transas parent fabrics thus produced, however, also had the characteristic stiffness, already noted. In carrying out this process the treatment with caustic soda at below 0 C. produces a stiff transparent material and that stiffness is not removed by the subsequent treatment with sulfuric acid at below 0 C. and of above 50.5 Be. as mentioned in the patent. ment with caustic alkali at 0 C. will by itself produce a stiff transparent material which still remains stiff after treatment with the sulfuric acid, I do not wish to include the treatment of such material in the claims hereto appended. Accordingly when I use the expression "soft in the claims as referring to cellulose-containing material, I intend material which has not been so treated bycaustic alkali toproduce this stiff transparent material mentioned in this patent. Similar processes are described in British Patent 103,432 and in German Patents 340,824 and 389,428, but these processes also result in products which are stiff and transparent and not soft and transparent. In these prior processes the disadvantage of stiffness is necessarily heightened by increase in the resulting transparency of the fabric; in other words the resulting fabrics become more and more hardened Since this treatand brittle according as the working conditions are adapted to production of themaximum transparency. Such brittleness and hardnws as pointed out under certain circumstances and in spite of excellent transparency may become so troublesome that known methods for certain purposes are no longer applicable thereto.

I have found in accordance with the present invention that soft transparent effects may be produced by the treatment of cellulosecontaining fiber products, fabrics, yarns and the like with sulfuric acid of over 50.5 B. at temperatures below 0 C. The sulfuric acid cooled to such low temperature may have incorporated therein stabilizing substances. Concentration of the sulfuric acid is preferably between 51 and 54 B. The temperature is preferably chosen at about minus 10 C. Experiments have disclosed the striking fact that strongly cooled sulfuric, acid of over 50.5 B. does not produce stiffening of the material but instead produces an cellulose-containing fibers transparent effects of a special kind with a softness which has never heretofore been known. This novel effect occurs only by the use of sulfuric acid concentrations of over 50.5 B..(specific gravity 1.54). The concentration above the critical value can be varied within wide limits. Sulfuric acid with gravity between 51 and 54 Be. is-particularly useful. The temperature of the acid should always be maintained so that it lies below C. during the treatment. When the temperature is minus 5 C. the effect becomes quite noticeable. Very favorable temperatures are those around minus (2., although further temperature variations within the range below the zero mark are permissible.

In addition to the novel effect, acid at low temperatures assures that hydrolytic decomposion of the fiber is inhibited and the fiber is thereby preserved. In certain cases certain substances may be incorporated in the sulfuric acid as stabilizers, for example pyridine, its homologues and derivatives, monoor polyvalent alcohols, ammonium salts, formaldehyde and formaldehyde. producing compounds.

The fibrous structures, if desired, may be subjected to the treatment without previous preparation or else they may be submitted to a suitable prior treatment by mercerization with caustic alkali or by bleaching. The acid-treated fabrics may be suitably subjected to a mercerizing after-treatment by mercerization with caustic alkali. The after-treatment is especially adapt ed to fabrics that have been given a prior mercerizing treatment with caustic alkali.

Even when strongly cooled sulfuric acid alone is brought to act upon the material, the novel effects mentioned become apparent, that is, with quicker or better transparency of the resulting product. The latter remains appreciably softer and more pliable than when the same acid is employed at the customary temperatures above 0 C. But the novel technical effect becomes far more conspicuous whenever the acid treatment practised at low temperatures is combined with the usual mercerization by means of caustic alkali. Mercerization may be pro uced prior or subsequent to the acid treatmen. Thelatter produces more-favorable effects. The use of two mercerizing treatments, that is, mercerization prior to acid treatment and the further mercerization applied thereafter produces particularly favorable results. According to the prescribed methods of working, transparent effects of particular clarity may be produced which possess theproperty of great softness.

The effects obtained by such treatment may be localized, that is, confined to certain limited portions with a view to producing patterns. By treatments known in the art as reserve or direct printing processes, pattern effects can be obtained in which an outstanding characteristic is that the transparent and opaque undertreated portions resemble one another very closely in their feel, possessing nearly the same soft and supple characteristics.

Fibrous structures refined in accordance with the new process here disclosed may be submitted to any dyeing and color-printing processes.

Owing to the special softness of the fabrics or structures, it has also become possible. to print these fabrics or structures in roller type printing machines without difllculty, a process which has been carried out with the greatest difficulty on the transparent fabrics heretofore available.

'The novel method here disclosed is particularly useful for treatment of cotton fabrics although all other' kinds-of filamentary fibrous structures 'as fabrics, textures, knitted goods. yarns and the like-fromr-cellulose containing fibers may be ennobled in this manner. v

In addition to cotton; other vegetable fibers such as linen, ramie and the like may be used The following examples are given to illustrate.

the invention:-

1. Bleached mercerized fine cotton batiste is drawn for 8 seconds through a bath of sulfuric acid of 52 B., kept at a temperature of minus 10 C. (measured at an outside temperature of C.) and is immediately rinsed. Next the fabric while still wet is mercerized-by caustic soda while tensioned (tautened or tentered) then washed and dried in the jigging frame (Riittelspannrahmen).

2. Bleached 'mixed fabric containing cotton and viscose is subjected to the action of sulfuric acid of 54 B. (measured at plus 15 C.) for 7 seconds at a temperature of minus 8". C. and is immediately thereafter washed to free it of all acid. Dryingis effected in a tenter.

3. Mercerized loosely twisted cotton yarn in simple filamentary form is drawn through a vat containing sulfuric acid of 53 B. (measured at plus 15C.) with an addition of 1% formaldehyde for a time of 12 seconds at minus 13 C. followed immediately by washing for perfect freedom from acid, and drying.

4. Resist-printed cotton muslin is caused to pass for 15 seconds through sulfuric acid of 51 B. (measured at plus 15 C.), at a temperature of minus 12 C. After squeezing out the liquid there the material is immediately washed with cold water and is then mercerized with soda lye. The material freed from alkali may 2. A process for producing ransparent mate rials which comprises treating soft cellulosecontaining material with sulfuric acid of a concentration above 50.5 B. at a temperature less than about 0 C. in the presence of a stabilizer,

thereby producing a transparent material with a softness near to that of the untreated material.

3. A process according to claim 1 in .which the concentration of the sulfuric acid employed is between 51 -54 B. I

4. A process according to claim 1 in which the temperature is maintained at about minus 10 Cels.

5. A process according to claim 1 in which at one stage of the treatment a mercerization is given to the material.

6. A process for producing transparent materials which. comprises treating soft cellulosecontaining material with sulfuric acid of a concentration above 50.5 B. at a temperature less than 0 C. and then mercerizing the so-treated material.

7. A process for producing pattern effects pleness of such portions about the same as the which comprises applying sulfuric acid of above untreated portions of the material. 50.5 B. at below 0 c. to localized portions of A nsm t c o in .fabric cellulose-containing material, thereby causing po fl softness an upp eness as permanent 5 the portions to which applied to become and inherent characteristics of said fabric, made 5 r m so as: m 5 in accordance with the process 0! claim 1. pa ent while rnaln lnlng e n a D V musrwmsa 

